This invention relates to an arrangement for abatement of the noise generated by turbofan drives, specifically in the hot gas area.
Active methods for abatement of the noise generated by turbofan drives in the hot gas area are known, for example, from U.S. Pat. No. 5,386,689. To abate noise in this way, sound sources are provided for generating antisound in the hot gas area of the drives.
German document DE 196 07 290 A1 describes an acoustic absorber consisting of a pot-shaped bottom part in which a single horn extends.
The object of this invention is to create an arrangement with which effective abatement of noise generated by turbofan drives in the hot gas area can be achieved while having a low weight in accordance with the requirements of aviation technology.
This object is achieved with the arrangement claimed. Advantageous embodiments are also claimed.
According to this invention, energy is withdrawn from the sound waves generated in the hot gas area of a turbofan drive by means of an absorbent lining of the hot gas area of the turbofan drive and then are no longer emitted. Dissipation is accomplished through viscous losses in the lining.
The lining is structured so that it has a plurality of adjacent cavities, with four horns extend into each cavity.
The horns have mouths attached to a perforated cover plate, and the cover plate forms a wall of the hot gas flow channel.
The invention will now be explained with reference to an exemplary embodiment shown in the drawings.